I use Wilton's cardboard cakeboards on top of a masonite board, and wrap both of them together in decorator foil. That way, when the party is over, I just separate them and send the leftover cake home on the cardboard one. Since I have family members that forget to return my leftover dishes in a timely manner....lol...I don't have to worry about when I'll get my masonite board back to put my next cake on.Besides, I like the extra strength the masonite board gives under a 11x15 sheet cake that is loaded with BC icing!

I love foamcore! Yes I make my own bases. you can go to Hobby Lobby and see two main thickness. Both have their advantages (that I could go on and on about). The thickest should be perfect for you. HL usually has their foamcore on sale about every other month 50% off. I stock up. If they dont have any there then I get a rain check.

If I don't want the cardboard back then I use pizza circles from GFS. I think the last time I bought them they were 10 cents a board? It's been awhile so I'm not sure on exact price. They had 3 different size circles. I tape, depending on the cake, 3 to 5 together to make a solid base.

For smaller cakes I use an old cardboard box, cut to fit the cake and wrapped with freezer paper. I'm so cheap I can't even pay 10 cents for a board.

For heavier cakes, especially those I have to transport, I have used leftover plywood or shelving cut to fit and wrapped with freezer paper. Of course, I sanitize the board before covering befroe covering heavily in freezer paper.

I don't sell the cakes so I don't have to worry about the customer's face when they realize their cake was on a piece of scrap plywood.